FMT230, FMT250
THERMAL MASS FLOWMETER | CI/FMT230/250-EN REV. B
45
8
Commissioning and operation
Safety instructions
DANGER
Danger of explosion if the device is operated with the
transmitter housing or terminal box open!
Before opening the transmitter housing or the terminal box,
note the following points:
• A valid fire permit must be present.
• Make sure that there is no explosion hazard.
• Switch off the power supply and wait for t > 20 minutes
before opening.
CAUTION
Risk of burns due to hot measuring media
The device surface temperature may exceed 70 °C (158 °F),
depending on the measuring medium temperature!
• Before starting work on the device, make sure that it has
cooled sufficiently.
Aggressive or corrosive media may lead to the damage of
wetted parts of the sensor. As a result, measuring medium under
pressure can leak out.
Wear to the flange gasket or process connection gaskets
(e.g. flange fitting or pipe fitting) may cause a pressurized
measuring medium to escape.
If pressure surges above the permissible nominal pressure of the
device occur permanently during operation, this may affect the
service life of the device.
If there is a chance that safe operation is no longer possible,
take the device out of operation and secure it against
unintended startup.
Note
For detailed information on the operation and parameterization
of the device, consult the associated operating instructions (OI)!
Write-protection switch, service LED and
local operator interface
1
Write protection switch
2
Service LED
3
Local operating interface
Figure 33: Operating elements in the terminal box
Write-protect switch
The write protection switch is located in the sensor terminal box.
If write protection is active, the parameterization of the device
cannot be changed via Modbus or the local operating interface.
Turning the write protection switch clockwise deactivates the
write protection function, while turning the switch counter-
clockwise activates it.
The power supply to the transmitter must be briefly interrupted
in order for the modified setting to take effect.
Service LED
The service LED, which indicates the operating condition of the
device, is located in the sensor terminal box.
Service LED
Description
Flashes rapidly (100 ms)
Starting sequence, device not yet ready for
operation
Lit up continuously
Device operating, no critical error
Flashes slowly (1 second)
A critical error has occurred, see
"Diagnosis /
error messages" in the operating instruction
Local operating interface
The sensor can also be parameterized without a Modbus
connection via the local operating interface, see
Parameterization via the local operating interface
on page 48.
